Powered air purifying respirators utilize a motor-driven blower unit to provide a forced flow of filtered air to the face of a wearer to ensure (in normal operation) that the wearer has an adequate supply of clean breathable air in a contaminated environment.
A major benefit to the wearer of a powered air purifying respirator, in comparison to a conventional non-powered respirator in which a filter is attached directly to the inlet of the facepiece, is that the wearer's lungs are relieved of the strain otherwise caused by inhalation against the resistance of the filter.
The motor-driven blower unit of a powered air purifying respirator can be carried on or near the waist of a wearer by a shoulder strap, a strap extending around the waist of the wearer, or both. Typically, a flexible hose is used to transport the air exiting from the blower to a facepiece worn about the face of the wearer.